Tamron Lenses - 3
Tamron 28-75mm f/2.8 Di III VXD G2 Lens
Tamron in the UK have kindly offered to loan me some of their latest lenses to check out their performance in IR;
First up is the newer version of the Tamron 28-75mm f/2.8, so this is the new G2 version, its slightly sharper than the already excellent original, however I do think there is slightly more of a hot spot as you stop the lens down. It is unlikely to be any problem in BW at any aperture, but I did find a slightly red patch in the centre of channel swapped false colour images. The false colour images above show that it is not too much of a problem, the shot on the right however shows the magnificent sharpness available even at f/2.8.
As always click on the images to open them larger in a new window, the above images are taken at 720nm on the left and 590nm on the right, both with Sony A7R series cameras.
Next up is the new Tamron 20-40mm f/2.8 Di VXD [A062] Lens
The shots above and left are taken with the new Tamron 20-40mm f/2.8 Di VXD [A062] lens and my 720nm Sony A7RIV, which may well be my new favourite lens for IR!!. It's small and light, 67mm filter size and a really useful focal length range. There is almost no IR hot spot issues at any focal length or aperture. The false colour image below at 20mm f/5.6 with a 590nm filter shows no problems at all. Certainly an excellent lens all round, not 100% into the corners, but that is always a problem with IR. It's so small it will fit into a coat pocket, the same cannot be said for the next lens!!
Tamron 35-150mm f/2.0-2.8 Di VXD [A058] Lens
I was surprised at the size of the Tamron 35-150 f/2.0-2.8 lens, I think I was expecting something similar to the Sony 24-70 f/2.8, but a 150mm f/2.8 is always going to be a whopper. Here are some images on my 720nm Sony A7R4 and 590nm A7R;
The 3 shots above are at 720nm at various apertures and again no hot spot problems at all, Tamron's latest designs seem to be getting better and better in IR. The false colour image on the left is with my Full Spectrum Sony A7R and a STC 590nm Clip In filter at 95mm and f/11. No hot spot problems at all, which is extremely unusual for a modern zoom lens, most of which would be hard pressed to have no hot spot problems in false colour with the aperture wide open let alone f/11 like this shot.
All in all an excellent lens for IR work, if a little on the large size. Almost no hot spots and great for False Colour at 590nm like the Tamron 20-40mm f/2.8 lens tested above. I look forward to receiving the newly announced Tamron 17-50mm f/4.0 lens, that could be the ideal range for IR work.
Tamron 50-400mm f/4.5-6,3 Di III VXD [A067] Lens
Not a focal length range often associated IR photography, but interesting never the less, especially since the lens starts at 50mm focal length. Here are a few images from my Full Spectrum Sony A7R with an STC 590nm Clip In filter;
The Tamron 50-400mm f4.5-6.3 Di III VXD [A067] lens is relatively compact and light for a full frame zoom of this range, it extends greatly as you zoom towards 400mm, but I didn't find the weight balance shifting uncomfortably. It's performance in IR was pretty similar to most of the other Tamron lenses tested to date, ie Excellent. There are very little signs of any hot spots in either 720nm Black and White or 590nm False Colour making any aperture or focal length suitable for excellent quality IR work. The only negative, was a hot area around the centre of the frame at 50mm at f/11 in 720nm, but this was very minor and could easily be dialed out by shifting the Blue slider to the left a touch in the Black and White conversion [In Photoshop].
So that's it for the time being, I am looking forward to testing the new Tamron 17-50mm f/4.0 lens as soon as a test lens becomes available. Thank you to Chris Watts at Tamron's UK importer; Transcontinenta UK for the loan of all of the lenses reviewed in these 3 web pages.